The veins of leaves are i) composed of xylem and phloem ii) continuous with vascular bundles in the stem and roots iii) finely branched to be in close contact with photosynthesizing cells

Hey there :)

All the options you have given are applicable. 

Because xylem and phloem are essentials as they are the veins of the leaves. They are bundled together in thin strands. They allow the movement of water and nutrients. 

The veins of leaves are finely branched to be in close contact with photosynthesizing cells as they need to store food.

Competition. interaction among organisms that compete for the same natural resource (food, shelter, water, space) in an ecosystem. predation. an interaction in which one organism kills another for food. predator. prey. symbiosis. mutualisum. commensalisum. parasitisum.

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